White told the online Texas Tribune that he doesn't think Perry should be referring to Obama in his television ads without using his title.

"As a citizen I call him president. President Obama," White said. "Whoever is the commander in chief, whether it be George W. Bush or President Obama, you need to refer to our president as our president."

Later, speaking to reporters outside the studio where the interview was being taped, White referred to the TV ad in which Perry says he "confronted Barack Obama," during the president's visit to Austin. Perry, as governor, greeted Obama at the Austin airport upon his arrival and gave him a letter asking the federal government to boost security along the Texas-Mexico border.

"We teach our kids and others to show respect to the office," White said.

A reporter then reminded the former Houston mayor that he sometimes calls the governor "Rick Perry" without using his title. "That's true," White said. "The office of the presidency, we've always treated as a special office."

Perry's campaign supplied media clips of White calling the president "Barack Obama" without the title, and White saying, "I was in the oil and gas business when he (Obama) was a community organizer."

During an interview with the Texas Tribune later Friday, Perry was asked why he keeps one schedule for state functions and another for political meetings and personal matters. Perry said he was following state guidelines.

"What I do with my private time, frankly, except for for the voyeurs of the world out there, is my business," Perry said.